Geological drilling constitutes an important component in the exploration of minerals, including but not limited to the exploration for iron ore. Such drilling provides information on lithologies that compose the geological model used in the estimation of resources and reserves.
In oil exploration, gamma-gamma geophysical well logging is one technique which provides methods for measurement of densities in drilling cores and samples. Such system may also be used for mineral exploration. However, several issues arise. In particular, in mineral exploration friable rock may cause the density measurements to be inaccurate. The removal of a drilling rod used to create the borehole can damage the edges of the borehole.
Further, a logging tool lowered into a borehole without a casing can become trapped down the borehole if the borehole collapses. A logging tool in the oil industry can be abandoned if it becomes stuck, since the oil exploration will never reach the point that the tool was stuck directly. However, in mineral exploration, such as iron ore exploration, the tool may be reached by miners and therefore present a hazard.